In typical monitoring systems, when an image angle of a camera is varied due to an earthquake or the like, the camera is calibrated again thereby to return the image angle of the camera to the original state. With a camera having the pan/tilt/zoom function, the orientation (angle) of the camera is stored, and thus when the camera is recovered from blackout or the like, the posture of the camera can be automatically recovered based on the stored angle.
On the other hand, there is also known a planetary exploration spacecraft for automatically correcting the orientation of a camera. The planetary exploration spacecraft detects the position of a specific star such as Canopus by a star tracker thereby to automatically correct the orientation of the camera.
Patent Literature 1 describes a monitoring camera correction device therein. The correction device described in Patent Literature 1 stores a reference pattern for giving a positional reference for correcting an offset of a shot image. The reference pattern is a modeled initial positional relationship for a specific part present in an already-known position in a monitored area. The correction device described in Patent Literature 1 corrects an image to match a comparative pattern with the reference pattern.